How do the decals, downtube cable guides and the headbadge compare? Does it use a 21.1mm BMX stem rather than a standard 22mm? Japanese or Taiwanese made? All of these details separate mine from the '84 and after mountain bikes, including the High Plains. However, several of these later bikes look very similar. My thought is that those frames might have been modeled after the one I have (specifically the bare frame/fork offered in 1983 with all its apparent variations) - though I don't pretend to have a prototype.